An Active Snubber Cell for N-Phase Interleaved DC-DC Converters

An active snubber cell and its dual circuit for reducing switching losses of 1- to N-phase dc-dc converter is presented. Main switch(es) of the converter can be turned-ON and turned-OFF at zero-voltage (ZV); a switch of the proposed snubber cell can be turned-ON at zero-current and turned-OFF at ZV. There are no extra current and voltage stresses will be introduced on the main switch; the reverse recovery current and the related loss from the main diode can also be reduced. The operating principle and the design procedure of the snubber cell will be given. The proposed active snubber cell can be applied in different dc-dc switching converters; the guidelines of integrating the cell will be illustrated. The performance of the proposed active snubber circuit has been evaluated on a 50-kHz per phase, 180 V-in, 400 V-out, and 2-kW interleaved boost converter prototype. Results show that the switching losses of the converter are significantly reduced, and the conversion efficiency is increased by 0.8% at rated load. The peak efficiency of the converter is > 97.9%. The experimental results are in good agreement with the theoretical predictions.